Interferon-gamma and TNF-alpha synergistically enhance the immunomodulatory capacity of Endometrial-Derived Mesenchymal Stromal Cell secretomes by differential microRNA and extracellular vesicle release

Endometrial Mesenchymal Stromal Cells (endMSCs) can be easily isolated from menstrual blood by plastic adherence. These cells have a potent pro-angiogenic and immunomodulatory capacity, and their therapeutic effect is mediated by paracrine mechanisms where secretome have a key role. In this paper, we aimed to evaluate different priming conditions in endMSCs using pro-inflammatory cytokines and Toll-Like Receptor ligands. Our in vitro results revealed a synergistic and additive effect of IFN{gamma} and TNF on endMSCs. The combination of these pro-inflammatory cytokines significantly increased the release of Indoleamine 2,3-dioxygenase (IDO1) in endMSCs. Additionally, this study was focused on the phenotype of IFN{gamma}/TNF-primed endMSCs (endMSCs*). Here we found that immune system-related molecules such as CD49d, CD49e, CD54, CD56, CD58, CD63, CD126, CD152, or CD274 were significantly altered in endMSCs* when compared to control cells. Afterward, our study was completed with the characterization of released miRNAs by Next Generation Sequencing (NGS). Briefly, our system biology approaches demonstrated that endMSCs* showed an increased release of 25 miRNAs whose target genes were involved in immune response and inflammation. Finally, the cellular and molecular characterization was completed with in vitro functional assays. In summary, the relevance of our results lies in the therapeutic potential of endMSCs*. The differences in cell surface molecules involved in migration, adhesion and immunogenicity, allowed us to hypothesize that endMSCs* may have an optimal homing and migration capacity towards inflammatory lesions. Secondly, the analysis of miRNAs, target genes and the subsequent lymphocyte activation assays demonstrated that IFN{gamma}/TNF-primed secretome may exert a potent effect on the regulation of adverse inflammatory reactions.